1. Field of the Invention
The present invention relates to a semiconductor device including transistors that are called an insulated gate transistor, a MIS (metal insulator semiconductor) field effect transistor or an MOS transistor, and more particularly to a semiconductor device that can be suitably mounted on an ink jet printer used as an output terminal such as a copying machine, a facsimile machine, a word processor or a computer, or on a liquid jet apparatus for manufacturing a DNA chip or an organic TFT, a method of manufacturing the same, and a liquid jet apparatus.
2. Related Background Art
Now, an example of a semiconductor device used in the liquid jet apparatus will be described.
In a recording apparatus used as various output terminals, an electro-thermal converter, an element that switches the electro-thermal converter element (hereinafter referred to as “switching element”), and a circuit for driving the switching element are mounted on a common substrate as a recording head.
FIG. 19 is a schematic cross-sectional view showing a part of a recording head according to a conventional structure.
Reference numeral 901 denotes a semiconductor substrate made of single crystal silicon. Reference numeral 912 is a p-type well region, 908 is an n-type drain region having a high impurity concentration, 916 is an n-type field relaxation drain region having a low impurity concentration, 907 is an n-type source region having a high impurity concentration, and 914 is a gate electrode. These elements form a switching element 930 using a MIS field effect transistor. Reference numeral 917 denotes a regenerative layer and a silicon oxide layer that functions as an insulating layer, 918 is a tantalum nitride film that functions as a heat resistant layer, 919 is an aluminum alloy film that functions as a wiring, and 920 is a silicon nitride film that functions as a protective layer. These elements form a substrate 940 of the recording head. In this example, reference numeral 950 denotes a heating portion, and an ink is jetted from 960. Also, a roof 970 defines a liquid passage 980 in cooperation with the substrate 940.
Incidentally, improvements have been frequently made to the recording head and the switching element structured as described above. In recent years, demands have been further made to increase a drive speed, to save an energy, to increase integration, to reduce the costs and to enhance the performance, with respect to such products.
A plurality of MIS field effect transistors 930 used as the switching elements shown in FIG. 19 are produced within the semiconductor substrate 901. And these MIS field effect transistors 930 are operated independently or at the same time to drive the connected electro-thermal converter.
However, when the conventional MIS field effect transistor 930 functions under the condition where a large current required to drive a load such as the electro-thermal converter flows, a pn reverse bias junction portion between a drain and a well generates a leak current since it cannot withstand a high electric field, and therefore it cannot satisfy a breakdown voltage required as a switching element. In addition, when the on resistance of the MIS field effect transistor used as the switching element is large, there arises such a problem to be solved that a current necessary to drive the electro-thermal converter cannot be obtained by resulting wasteful current consumption.